In his book the Ethics of Liberty, Murray Rothbard sets out the links between individual liberty, property rights, and the non-aggression principle. Rothbard’s explanation of property rights as the essence of liberty has greatly influenced the libertarian understanding of the NAP, but there is often a great deal of confusion as to what amounts to an act of aggression. As David Gordon has pointed out, some libertarians have gone so far as to say that the NAP should be rejected altogether for having “morally unacceptable implications.”
One mistake many libertarians make is to suppose that theoretical principles can provide a complete resolution for difficult cases, in the sense that we should be able to ascertain—just by studying the NAP—whether it has been violated in specific cases. Gordon points out that this overlooks the role of other considerations, such as social conventions and legal norms, in resolving real world disputes. The “morally unacceptable implications” that many libertarians find disturbing are the result of theorizing about the NAP without regard to the broader ethical framework within which Rothbard defends property rights. Rothbard’s theory of liberty is not just a philosophical or academic treatise based on a set of hypothetical problems. It is also a “system of libertarian law” designed as a foundation for “the truly successful functioning of what we may hope will be the libertarian society of the future.”
Rothbard’s analysis therefore takes into account the real-world context of crime and aggression. He defines an act of aggression as a violation of another’s liberty, and, importantly, sees liberty as an emanation of self-ownership and private property. He explains how these ideas are interlinked:
The key to the theory of liberty is the establishment of the rights of private property, for each individual’s justified sphere of free action can only be set forth if his rights of property are analyzed and established. “Crime” can then be defined and properly analyzed as a violent invasion or aggression against the just property of another individual (including his property in his own person).
In this context, he defines a crime as a violation of property rights. Thus, Rothbard defines “aggressive violence” as a situation where:
…one man invades the property of another without the victim’s consent. The invasion may be against a man’s property in his person (as in the case of bodily assault), or against his property in tangible goods (as in robbery or trespass). In either case, the aggressor imposes his will over the natural property of another—he deprives the other man of his freedom of action and of the full exercise of his natural self-ownership.
Rothbard’s explanation of the NAP clearly includes invasions of both person and property. But many people struggle to apply these principles in real cases. The first practical difficulty arises in relation to “mere” threats. Rothbard sees direct, overt, threats of invasion as equivalent to invasion because—as he sees it—the NAP is about the invasion of the person or property of another and depriving another man of his freedom to exercise his self-ownership and ownership of his property.
A violation of another man’s liberty may be committed by means of intimidation, or fraud, which Rothbard sees as “equivalent to the invasion itself.” Does this mean that any time someone feels (or claims to feel) “intimidated” that is the equivalent of an invasion? Of course not. Under the NAP, violence against another is only justified in self-defense, and we must therefore have recourse to the principles of self-defense in ascertaining whether an act of violence is aggressive or defensive. Rothbard holds that “defensive violence may only be used against an actual or directly threatened invasion of a person’s property, and may not be used against any nonviolent ‘harm’ that may befall a person’s income or property value.” Further, as Rothbard explains, in cases of direct threat of invasion, self-defense may be justified even before a physical act of violence has yet occurred:
Defensive violence, therefore, must be confined to resisting invasive acts against person or property. But such invasion may include two corollaries to actual physical aggression: intimidation, or a direct threat of physical violence; and fraud, which involves the appropriation of someone else’s property without his consent, and is therefore “implicit theft.” Thus, suppose someone approaches you on the street, whips out a gun, and demands your wallet. He might not have molested you physically during this encounter, but he has extracted money from you on the basis of a direct, overt threat that he would shoot you if you disobeyed his commands. He has used the threat of invasion to obtain your obedience to his commands, and this is equivalent to the invasion itself.
Rothbard does not suppose that any “mere threat” is “equivalent to the invasion itself.” He emphasizes that: “It is important to insist, however, that the threat of aggression be palpable, immediate, and direct; in short, that it be embodied in the initiation of an overt act” (emphasis added). This is where many libertarians begin to get confused. They want to know how we would distinguish between “mere threats” and “palpable, immediate, and direct” threats. They suppose that Rothbard’s theory is somehow inadequate as it does not definitively classify direct and indirect threats. But no legal theory can determine whether an act is “palpable, immediate, and direct”—to ascertain this it is necessary to examine the facts.
This is why the outcome of real-world cases depends, not only on the applicable legal principles, but also on the relevant facts—and there is often much dispute over which facts count as relevant or how much importance ought to be attached to specific facts. For example, it is easy enough to state that invading another’s property is an act of aggression, and that invasion occurs when one intrudes upon the property of another without consent. But in practical cases what counts as an “intrusion”? What counts as “consent”? Does a stranger “intrude” when he walks up to someone’s front door without permission, and rings the doorbell? Would that depend on the time of day, the stranger’s purpose, or even his demeanor? Perhaps if he just emerged from what appears to be a delivery vehicle and has what appears to be a parcel in his hand we might “imply” consent to deliver parcels, but if he approaches under cover of darkness with a weapon in his hand we would take a different view of the matter. Moreover, to say that consent may be “implied” in appropriate circumstances does not tell us which are the circumstances in which consent ought to be implied. The theory of non-aggression, by itself, cannot conclusively answer these types of questions.
Gordon adverts to this problem when he explains that, while Rothbard regarded pollution as an invasion of property, this principle would not, in itself, determine what types of polluting activity count as an invasion. He discusses the example of smoke: if you are smoking a cigarette as you walk down the street, does your smoke “invade” the properties you walk past thereby violating other people’s property rights? Some libertarians ran this argument during the covid outbreak, arguing that mere breathing amounted to an act of aggression against other people and therefore justified “restraining” or even attacking potential “covidiots” who ran around wantonly breathing out their germs. Attacking them would be an act of “self-defense” that would save grandma’s life, or so the reasoning went. Walter Block described that position as follows:
For anyone venturing forth onto the streets would necessarily be violating the NAP. It is as if he is automatically shooting a gun at random or swinging his fists without being able to stop. As such he constitutes a threat. The NAP proscribes not only physical invasions but also the threat thereof. Under the scenario we have depicted, this is indeed the case, only instead of bullets or punches the traveler would be hurling a deadly virus at everyone else.
That some libertarians reasoned in that way is not due to any failing of the NAP, but rather a failure to grasp accurately the facts of the case. Gordon explains that while the non-aggression principle defines acts of aggression, definitions alone do not suffice in answering practical questions. As shown by the covid example, the definition of the NAP may be correct, but the application of it to the facts may nevertheless be entirely wrong. To resolve real cases, something more than definitions and theories are needed, one of which Gordon describes as social convention: “the understanding that prevails in a society.” Recourse to matters of convention would help to resolve many problems that needlessly confuse libertarians. To illustrate this, consider Walter Block’s example in which he distinguishes analytically between a “mere” threat and “initiation of physical violence”:
A approaches B and points a gun at him. A says to B: “Give me your money or I’ll shoot you.” Surely, a rights violation has now occurred; the libertarian nonaggression principle includes “mere” threats such as these, not only the initiation of physical violence.
Although there is clearly an analytical distinction between a “mere” threat and “physical violence,” in Block’s example no reasonable person would doubt that A is a violent aggressor. The distinction between threat and violence—while analytically interesting—is moot in the fact scenario Block has presented. This is indeed the precise example Rothbard uses to illustrate that in some cases a threat is the equivalent of an invasion. In such cases, the threat is no “mere” threat—it amounts to “the initiation of physical violence.” As Rothbard explains it, the “rights violation,” namely the invasion of property rights, consists in the act of aggression itself, which in this case is the threat to shoot. To apply Rothbard’s words, in this case the “crime” is “a violent invasion or aggression against the just property of another individual [and] his property in his own person” committed by A when A pointed a gun at B and threatened to shoot. Any reasonable person would regard that as “the initiation of physical violence,” even though the trigger has not yet been pulled, and may or may not end up being pulled, for example, if A is interrupted before he has the chance to shoot.
Block is, therefore, right to observe that, “A has violated the rights of B even if he breaks off the encounter and runs away, leaving B with his wallet intact.” But in distinguishing analytically between the “threat” and the “initiation of physical violence,” Block overlooks the common sense fact that based on the facts he presented, the threat itself constitutes initiation of physical violence. Even though he argues that both violate the NAP, the point is that separating the threat from the initiation of violence—based on these facts—is an analytical distinction that serves only to confuse and not to clarify. Most people faced with a gun-wielding attacker would not have any difficulty about whether to “classify” that as a threat or as an attack. It is not just that “both” are acts of aggression, but that, based on these facts, there is no real-world distinction between the “threat” and the “violence.” The threat and the violence are “equivalent,” to use Rothbard’s word.
Common sense and close attention to the facts of the case go a long way in resolving such problems. It would be nonsensical to ask whether someone with a gun to your head threatening to shoot you has committed an act of violence. Indeed, the confused libertarian might ask, what if—unknown to the aggressor—the gun was not loaded? Should we then say there is no act of violence until the moment the bullet leaves the gun? But—the libertarian might persist—what if the bullet leaves the gun but misses the target? Should we then say there is no act of violence until the bullet hits the target? Under ordinary principles of self-defense, based on these facts, there is no need for B to wait for A to pull the trigger before taking defensive action. It is by convention—reflected in the legal norms of the traditional English common law—that we understand that an armed robber is a violent aggressor.
If the facts were different, the situation would, of course, be re-evaluated accordingly. This is precisely why resolving criminal cases involves an application of the principles to the facts. It is not merely a matter of theoretical disputation. This point is highlighted by Rothbard in his article War Guilt, which deals specifically with assigning guilt for the wars in the Middle East but also contains lessons that may be extrapolated to other cases. Rothbard reminds us that in any war, you cannot simply rely on theories of non-aggression to ascertain who is the aggressor and who is fighting defense. He criticizes the “tendency to avoid bothering about the detailed pros and cons of any given conflict” and cautions that, “Libertarians must come to realize that parroting ultimate principles is not enough for coping with the real world.” The same observation also applies to other contexts in which the non-aggression principle is applied. To ascertain whether—and, if so, by whom—an act of aggression has been committed, theoretical debates do not suffice. A close and detailed examination of the relevant facts is necessary.
